CN114846670A - Solid-state battery - Google Patents

Abstract

The invention provides a solid-state battery which can sufficiently prevent the reduction of a theoretical capacity ratio calculated according to the content of an active material even when a positive electrode current collecting layer is not provided for improving capacity density (for example, energy density), and can sufficiently prevent the reduction of capacity characteristics and load characteristics compared with the case of not containing a conductive material. The present invention relates to a solid-state battery comprising a solid-state battery laminate (100), a positive electrode terminal (40A), and a negative electrode terminal (40B), wherein the solid-state battery laminate (100) comprises at least one battery-constituting cell along a lamination direction, the battery-constituting cell comprises a positive electrode layer (10A), a negative electrode layer (10B), and a solid electrolyte layer (20) interposed between the positive electrode layer and the negative electrode layer, the positive electrode terminal (40A) and the negative electrode terminal (40B) are respectively provided on opposite side surfaces of the solid-state battery laminate, the positive electrode layer (10A) has an end surface current collecting structure for collecting current at an end surface (10A1) of the positive electrode layer, and is in contact with a positive electrode current collecting portion (11) at an end surface (10A1) of the positive electrode layer, and is electrically connected to the positive electrode terminal (40A) via the positive electrode current collecting portion (11), the positive electrode layer (10A) contains a conductive carbon material.

Description

Solid-state battery

Technical Field

The present invention relates to a solid-state battery. More specifically, the present invention relates to a laminated solid-state battery in which layers constituting a battery constituent unit are laminated.

Background

Conventionally, secondary batteries that can be repeatedly charged and discharged have been used for various applications. For example, secondary batteries are used as power sources for electronic devices such as smart phones and notebook computers.

In a secondary battery, a liquid electrolyte is generally used as a medium for ion movement that contributes to charge and discharge. That is, a so-called electrolytic solution is used for the secondary battery. However, such a secondary battery generally requires safety in terms of preventing leakage of the electrolyte. Further, since organic solvents and the like used for the electrolytic solution are combustible substances, safety is also required in this respect.

Therefore, a solid-state battery using a solid electrolyte instead of an electrolytic solution has been studied. For example, as shown in fig. 6, patent document 1 describes a solid-state battery 250 including a positive electrode current collecting layer 201, a positive electrode active material layer 202, a solid electrolyte layer 203, a negative electrode active material layer 204, and a negative electrode current collecting layer 205, in which at least one of the positive electrode current collecting layer, the positive electrode active material layer, the negative electrode active material layer, and the negative electrode current collecting layer contains a carbon material and glass. In the solid-state battery 250, for example, the positive electrode active material layer 202 is laminated on the positive electrode current collecting layer 201, and therefore current is collected on the main surface 2020 of the positive electrode active material layer 202.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2018-170189

The inventors of the present invention have found the following new problems: in the case of a structure in which an electrode layer is laminated on an electrode collector layer, the number of lamination increases, so that the yield and quality are reduced, and/or the manufacturing cost is increased. In order to improve the yield and quality and reduce the manufacturing cost, it is preferable to reduce the number of lamination as much as possible. If the electrode collector layer can be eliminated, the number of times of lamination can be reduced, and the effects of improving yield and quality and reducing manufacturing cost can be expected.

Therefore, when the electrode current collecting layer is removed and the end of the positive electrode layer is extended to the positive electrode terminal, a portion of the positive electrode layer where the negative electrode layer is not present is formed at the facing portion, and the current is concentrated at the end of the negative electrode layer, which causes a problem that lithium dendrite precipitates and short circuits frequently occur. In order to solve this problem while taking advantage of the reduction in the number of lamination, a positive electrode collector may be disposed beside the positive electrode layer, and the positive electrode layer and the positive electrode terminal may be electrically connected through this positive electrode collector. However, in this case, a new problem is found in that the electron conductivity of the positive electrode layer decreases, and the theoretical capacity ratio calculated from the active material content decreases. That is, there arises a problem that the capacity that can be actually extracted is significantly reduced as compared with the theoretical capacity calculated from the active material content.

The present invention aims to provide a solid-state battery which can sufficiently prevent a decrease in the theoretical capacity ratio calculated from the active material content and a short circuit caused by current concentration at the end of a negative electrode layer even when the solid-state battery does not have a positive electrode current collecting layer, and can sufficiently prevent a decrease in the capacity characteristics and load characteristics compared to the case where the solid-state battery does not contain a conductive material.

Disclosure of Invention

The present invention relates to a solid-state battery comprising a solid-state battery laminate, a positive electrode terminal and a negative electrode terminal,

the solid battery laminate is provided with at least one battery constituting unit along the lamination direction, the battery constituting unit is provided with a positive electrode layer, a negative electrode layer and a solid electrolyte layer between the positive electrode layer and the negative electrode layer,

the positive electrode terminal and the negative electrode terminal are respectively provided on opposite side surfaces of the solid-state battery stack,

the positive electrode layer has an end surface current collecting structure for collecting current at an end surface of the positive electrode layer, and is in contact with a positive electrode current collecting portion at the end surface of the positive electrode layer and electrically connected to the positive electrode terminal via the positive electrode current collecting portion,

the positive electrode layer contains a conductive carbon material.

The solid-state battery according to the present invention does not have a positive electrode current collecting layer, and the number of laminations in the manufacturing process of the solid-state battery is reduced, so that the yield and quality can be improved, and the manufacturing cost can be reduced.

The solid-state battery according to the present invention has a structure in which the positive electrode layer is electrically connected to the positive electrode terminal via the positive electrode current collector, and the formation of a portion of the positive electrode layer, which is not provided with the negative electrode layer, at the facing portion can be more sufficiently prevented, so that short-circuiting due to current concentration at the end portion of the negative electrode layer can be more sufficiently prevented.

The solid-state battery according to the present invention can more sufficiently prevent a decrease in the theoretical capacity ratio calculated from the active material content, and can more sufficiently prevent a decrease in the capacity characteristics and the load characteristics than the case where the solid-state battery does not contain the conductive material.

Drawings

Fig. 1 is a perspective view schematically showing the external appearance of a solid-state battery according to an embodiment of the present invention.

Fig. 2 is a schematic sectional view when the section a-a of the solid-state battery of fig. 1 is viewed in the direction of the arrow.

Fig. 3 is a plan view schematically showing the solid-state battery of fig. 2, and is a top perspective view of the positive electrode layer, the positive electrode current collecting portion, and the negative electrode layer.

Fig. 4A is a plan view schematically showing the positive current collecting portion and its vicinity in the solid-state battery of fig. 3.

Fig. 4B is a plan view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

Fig. 4C is a plan view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

Fig. 4D is a plan view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

Fig. 4E is a plan view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

Fig. 4F is a plan view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

Fig. 5A is a cross-sectional view schematically showing the positive electrode current collecting portion and its vicinity in the solid-state battery of fig. 3.

Fig. 5B is a cross-sectional view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

Fig. 5C is a cross-sectional view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

Fig. 5D is a cross-sectional view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

Fig. 5E is a cross-sectional view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

Fig. 5F is a cross-sectional view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

Fig. 5G is a cross-sectional view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

Fig. 5H is a cross-sectional view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

Fig. 6 is a cross-sectional view schematically showing a solid-state battery according to the related art.

Detailed Description

[ solid-state Battery ]

Hereinafter, the "solid-state battery" of the present invention will be described in detail. Although the description is made with reference to the drawings as necessary, the drawings are only schematically and exemplarily shown for understanding the present invention, and the appearance, the size ratio, and the like may be different from the real ones.

The term "solid-state battery" as used herein refers to a battery in which constituent elements are made of a solid substance in a broad sense, and refers to an all-solid-state battery in which constituent elements (particularly, preferably, all constituent elements) are made of a solid substance in a narrow sense. In a preferred embodiment, the solid-state battery according to the present invention is a laminated solid-state battery in which layers forming a battery constituent unit are laminated, and such layers are preferably made of a sintered body. The term "solid-state battery" includes not only a so-called "secondary battery" capable of repeated charge and discharge but also a "primary battery" capable of discharge only. In a preferred embodiment of the present invention, the "solid-state battery" is a secondary battery. The term "secondary battery" is not limited to this name, and may include an electrochemical device such as an "electricity storage device".

The term "plan view" as used herein refers to a form in which an object is viewed from above or below in a thickness direction based on a stacking direction of layers constituting a solid-state battery, and includes plan views (top and bottom views). The term "cross-sectional view" as used herein refers to a form when viewed from a direction substantially perpendicular to a thickness direction in a lamination direction of layers constituting the solid-state battery (in short, a form when cut along a plane parallel to the thickness direction), and includes cross-sectional views. In particular, the "cross-sectional view" may be a view taken along a plane parallel to the thickness direction in the stacking direction of the layers constituting the solid-state battery, that is, a plane passing through the positive electrode terminal and the negative electrode terminal. The "vertical direction" and the "horizontal direction" used directly or indirectly in the present specification correspond to the vertical direction and the horizontal direction in the drawings, respectively. Unless otherwise indicated, like reference numbers or designations indicate like elements, parts, or meanings. In a preferred embodiment, it can be understood that a vertical direction downward (i.e., a direction in which gravity acts) corresponds to a "downward direction", and an opposite direction corresponds to an "upward direction".

The solid-state battery 200 according to the present invention is configured to include a solid-state battery laminate 100, a positive electrode terminal 40A, and a negative electrode terminal 40B, as shown in fig. 1, 2, and 3, for example,

the solid battery laminate 100 includes at least one battery constituting unit including a positive electrode layer 10A, a negative electrode layer 10B, and a solid electrolyte layer 20 interposed therebetween, along the lamination direction L,

the positive electrode terminal 40A and the negative electrode terminal 40B are provided on the opposite side surfaces of the solid-state battery stack 100, respectively.

In the solid battery laminate 100, positive electrode layers 10A and negative electrode layers 10B are alternately laminated with solid electrolyte layers 20 interposed therebetween. Fig. 1 is a perspective view schematically showing the external appearance of a solid-state battery according to an embodiment of the present invention. Fig. 2 is a schematic sectional view when a section a-a of the solid-state battery of fig. 1 is viewed in the direction of arrows. Fig. 3 is a plan view schematically showing the solid-state battery of fig. 2, and is a perspective plan view of positive electrode layer 10A, positive electrode collector 11, and negative electrode layer 10B.

In the solid-state battery, the respective layers constituting the solid-state battery are formed by firing, and the positive electrode layer 10A, the negative electrode layer 10B, the solid electrolyte layer 20, and the like form sintered layers. Preferably, positive electrode layer 10A, negative electrode layer 10B, and solid electrolyte layer 20 are each integrally fired with one another, and thus the battery constituent unit forms an integrally sintered body.

(Positive electrode layer)

Positive electrode layer 10A has an end surface current collecting structure. Positive electrode layer 10A having the end surface current collecting structure means that positive electrode layer 10A has a structure in which current is collected at end surface 10A1 (particularly, only the end surface) of positive electrode layer 10A. Specifically, positive electrode layer 10A is in contact with positive electrode current collecting portion 11 at end face 10A1 (particularly, only the end face) of positive electrode layer 10A, and is electrically connected to positive electrode terminal 40A via positive electrode current collecting portion 11 (particularly, only the positive electrode current collecting portion). The end face 10A1 of the positive electrode layer 10A is a face (for example, a side face) that faces the positive electrode terminal 40A, among faces (for example, side faces) that connect two main faces (i.e., the upper face 10A2 and the lower face 10A3) perpendicular to the stacking direction L, among the outer faces that constitute the positive electrode layer 10A. The main surface is a relatively large area surface. Collecting at the end face 10a1 means that electrons come in and go out from the end face 10a1 (particularly, only the end face). In the present invention, since positive electrode layer 10A has an end surface current collecting structure, a so-called current collecting layer, which is necessary for a main surface current collecting structure described later, can be omitted. As a result, the number of times of lamination can be reduced, the yield can be improved, and the manufacturing cost can be suppressed. When positive electrode layer 10A has a main surface current collecting structure described later, the number of times of lamination increases, and therefore, the yield is deteriorated and the manufacturing cost is increased. Most preferably, positive electrode layer 10A is in contact with positive current collecting portion 11 only at end face 10A1, but at the boundary between positive electrode layer 10A and positive current collecting portion 11, either one of positive electrode layer 10A and positive current collecting portion 11 may cover the other.

In the end surface current collecting structure of positive electrode layer 10A, positive electrode layer 10A does not necessarily have to be electrically connected to positive electrode terminal 40A via positive electrode current collecting portion 11, and may be in direct contact with positive electrode terminal 40A at end surface 10A1 (particularly, only the end surface) of positive electrode layer 10A and be electrically connected to positive electrode terminal 40A directly, without via positive electrode current collecting portion 11, for example. From the viewpoint of efficiently exchanging ions with the negative electrode, positive electrode layer 10A is preferably in contact with positive electrode current collecting portion 11 at end face 10A1 (particularly, only the end face) of positive electrode layer 10A, and is preferably electrically connected to positive electrode terminal 40A via positive electrode current collecting portion 11.

In a preferred embodiment of the end surface current collecting structure of positive electrode layer 10A, positive electrode layer 10A and positive electrode current collecting portion 11 are usually in contact with each other at the end surfaces. In other words, end surface 10A1 of positive electrode layer 10A is in contact with end surface 111 of positive current collecting portion 11. Therefore, as shown in fig. 2, for example, positive electrode layer 10A and positive electrode current collecting portion 11 have a structure that they are adjacent to each other in a direction perpendicular to stacking direction L in cross-sectional view. For example, as shown in fig. 3, positive electrode layer 10A and positive electrode current collecting portion 11 are also configured to be adjacent to each other in a direction perpendicular to stacking direction L in a plan view.

The positive electrode collector portion 11 generally has an upper surface 112 coplanar with the upper surface 10A2 in the stacking direction L of the positive electrode layer 10A, and has a lower surface 113 coplanar with the lower surface 10A3 in the stacking direction L of the positive electrode layer 10A. The coplanar state refers to a state in which there is no height difference between two surfaces. The two surfaces are upper surface 10A2 of positive electrode layer 10A and upper surface 112 of positive current collecting unit 11, and lower surface 10A3 of positive electrode layer 10A and lower surface 113 of positive current collecting unit 11.

As shown in fig. 3 and 4A, positive electrode collector portion 11 extends from positive electrode layer 10A side to positive electrode terminal 40A side. In these figures, the extending direction is represented by "K". Fig. 4A is a plan view schematically showing the positive current collecting portion and its vicinity in the solid-state battery of fig. 3.

In fig. 3 and 4A, positive electrode current collecting portion 11 has a constant width direction W dimension in extension direction K equal to that of positive electrode layer 10A in a plan view, but is not limited thereto.

For example, as shown in fig. 4B, positive electrode current collector 11 may have a width W dimension larger than that of positive electrode layer 10A in a plan view and constant in the extending direction K.

For example, as shown in fig. 4C, the width direction W of positive electrode current collecting portion 11 in a plan view may gradually increase from the same width direction W as that of positive electrode layer 10A toward positive electrode terminal 40A (or extending direction K).

From the viewpoint of reducing the electrical resistance and improving the current collection efficiency due to an increase in the contact area between positive electrode current collection unit 11 and positive electrode terminal 40A, positive electrode current collection unit 11 preferably has a shape in plan view as shown in fig. 4B and 4C. Fig. 4B is a plan view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention. Fig. 4C is a plan view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

In fig. 3 and 4A to 4C, positive electrode collector portion 11 is in contact with only 1 side in the planar shape (for example, rectangular shape) of positive electrode layer 10A in the planar view, but is not limited thereto.

For example, as shown in fig. 4D, positive electrode collector portion 11 may be in contact with 2 sides of positive electrode layer 10A in a planar view (for example, rectangular shape). The shape of positive electrode collector portion 11 in plan view is referred to as a 2-side surrounded shape. Fig. 4D is a plan view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

For example, as shown in fig. 4E, positive electrode collector portion 11 may be in contact with 3 sides of positive electrode layer 10A in a planar view (for example, rectangular shape). The shape of positive electrode collector portion 11 in plan view is referred to as a 3-sided enclosure type shape. Fig. 4E is a plan view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

For example, as shown in fig. 4F, positive electrode collector portion 11 may be in contact with 4 sides of positive electrode layer 10A in a planar view (for example, rectangular shape). The shape of positive electrode collector portion 11 in plan view is referred to as a 4-sided enclosure type shape. Fig. 4F is a plan view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

From the viewpoint of reducing the resistance and improving the current collection efficiency based on the reduction in the average distance between the positive electrode active material and the positive electrode current collecting portion 11 in the positive electrode layer 10A, the positive electrode current collecting portion 11 preferably has a 2-4 side-enclosure type plan view shape shown in fig. 4D, 4E, and 4F, more preferably has a 3-4 side-enclosure type plan view shape shown in fig. 4E and 4F, and still more preferably has a 4-side-enclosure type plan view shape shown in fig. 4F.

In fig. 2 and 5A, boundary P between end surface 111 on the positive electrode collector portion 10A side in positive electrode collector portion 11 and end surface 10A1 on the positive electrode collector portion 11 side in positive electrode layer 10A has a cross-sectional shape shown by a straight line parallel to stacking direction L in cross-sectional view, but is not limited thereto.

For example, as shown in fig. 5B, the boundary P may have a linearly inclined cross-sectional shape that is linearly distant from the positive electrode terminal 40A from the upper surface (10A2, 112) side toward the lower surface (10A3, 113) side in cross-sectional view. Fig. 5B is a cross-sectional view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

For example, as shown in fig. 5C, the boundary P may have a cross-sectional shape of a straight line inclined from the upper surface (10A2, 112) side toward the lower surface (10A3, 113) side to linearly approach the positive electrode terminal 40A in cross-sectional view. Fig. 5C is a cross-sectional view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

For example, as shown in fig. 5D, the boundary P may have a curved oblique cross-sectional shape that is curvilinearly distant from the positive electrode terminal 40A from the upper surface (10A2, 112) side toward the lower surface (10A3, 113) side in cross-sectional view. Fig. 5D is a cross-sectional view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

For example, as shown in fig. 5E, the boundary P may have a positive current collector side circular convex sectional view shape (for example, a positive current collector side semi-circular convex sectional view shape) that curves away after curvilinearly approaching the positive electrode terminal 40A from the upper surface (10A2, 112) side toward the lower surface (10A3, 113) side in sectional view. The positive electrode current collecting portion side circular projection type cross-sectional observation shape is a cross-sectional observation shape that projects substantially circularly (for example, substantially semicircular) toward the positive electrode current collecting portion side. Fig. 5E is a cross-sectional view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

For example, as shown in fig. 5F, the boundary P may have a positive-electrode-layer-side circular-protrusion-type cross-sectional shape (for example, a positive-electrode-layer-side semi-circular-protrusion-type cross-sectional shape) that curves away from the positive-electrode terminal 40A from the upper surface (10A2, 112) toward the lower surface (10A3, 113) in a cross-sectional view and then curves toward each other. The positive electrode layer side circular cross-sectional observation shape is a cross-sectional observation shape that protrudes toward the positive electrode layer side in a substantially circular shape (for example, a substantially semicircular shape). Fig. 5F is a cross-sectional view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

For example, as shown in fig. 5G, the boundary P may have a sectional view shape of a positive electrode collector side angular protrusion (for example, a sectional view shape of a positive electrode collector side triangular protrusion) that linearly approaches the positive electrode terminal 40A from the upper surface (10A2, 112) side toward the lower surface (10A3, 113) side and then linearly separates therefrom in a sectional view. The positive electrode current collecting portion side angular protrusion type cross-sectional observation shape is a cross-sectional observation shape that protrudes to the positive electrode current collecting portion side in a substantially angular shape (for example, a substantially triangular shape). Fig. 5G is a cross-sectional view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

For example, as shown in fig. 5H, the boundary P may have a positive electrode layer side angular cross-sectional shape (for example, a positive electrode layer side triangular cross-sectional shape) that linearly moves away from the positive electrode terminal 40A from the upper surface (10A2, 112) side toward the lower surface (10A3, 113) side in a cross-sectional view and then linearly approaches. The positive electrode layer side angular cross-sectional observation shape is a cross-sectional observation shape that protrudes toward the positive electrode layer side in a substantially angular shape (for example, a substantially triangular shape). Fig. 5H is a cross-sectional view schematically showing another example of the positive electrode current collecting portion and its vicinity in the solid-state battery according to the present invention.

For example, the boundary P may have a composite cross-sectional observation shape in which two or more of the above shapes are combined.

From the viewpoint of reducing the electrical resistance and improving the current collection efficiency based on the increase in the contact area between positive electrode layer 10A and positive electrode current collection unit 11, boundary P preferably has a cross-sectional shape of a straight line or a curved line inclined type as shown in fig. 5B, 5C, and 5D, or a cross-sectional shape of a positive electrode current collection unit side circular protrusion type or a positive electrode current collection unit side angular protrusion type as shown in fig. 5E and 5G, and more preferably has a cross-sectional shape of a positive electrode current collection unit side circular protrusion type or a positive electrode current collection unit side angular protrusion type as shown in fig. 5E and 5G.

Positive electrode layer 10A is an electrode layer including at least a positive electrode active material and a conductive carbon material. Positive electrode layer 10A may further include a solid electrolyte. In a preferred embodiment, the positive electrode layer is composed of a sintered body containing at least a positive electrode active material, a conductive carbon material, and a solid electrolyte. By including the conductive carbon material in the positive electrode layer 10A, even when the solid-state battery does not have a positive electrode current collecting layer in order to increase the capacity density (for example, energy density), it is possible to sufficiently prevent a decrease in the theoretical capacity ratio calculated from the active material content, and to sufficiently prevent a decrease in the capacity characteristics and load characteristics as compared with the case where the conductive material is not included. When the positive electrode layer 10A does not contain the conductive carbon material, the decrease in the theoretical capacity ratio calculated from the active material content cannot be sufficiently prevented without the positive electrode current collecting layer. In the present specification, the positive electrode current collector layer is formed on the main surface (or the entire surface) of the positive electrode layer, and as a result, the current collector member is disposed adjacent to the positive electrode layer in the stacking direction of the positive electrode layer, the negative electrode layer, and the like. The positive current collecting portion is a current collecting member formed between the positive electrode layer and the positive electrode terminal so as to be adjacent to the positive electrode layer in a direction perpendicular to the stacking direction of the positive electrode layer, the negative electrode layer, and the like, and is different from the arrangement of the positive current collecting layer (particularly, the direction adjacent to the positive electrode layer).

The positive electrode active material contained in the positive electrode layer 10A is a material participating in the transfer of electrons in the solid-state battery. Charge and discharge are performed by carrying out movement (conduction) of ions between the positive electrode layer and the negative electrode layer via the solid electrolyte and transfer of electrons between the positive electrode layer and the negative electrode layer via an external circuit. The positive electrode layer is preferably a layer capable of intercalating and deintercalating lithium ions or sodium ions (particularly lithium ions). That is, the solid-state battery of the present invention is preferably an all-solid-state secondary battery in which lithium ions or sodium ions (particularly lithium ions) move between the positive electrode layer and the negative electrode layer via the solid electrolyte to perform charging and discharging of the battery.

The positive electrode active material is, for example, a lithium-containing compound. The type of the lithium-containing compound is not particularly limited, and examples thereof include a lithium transition metal complex oxide and a lithium transition metal phosphate compound. The lithium transition metal composite oxide is a generic name of oxides containing lithium and one or two or more transition metal elements as constituent elements. The lithium transition metal phosphate compound is a generic name of a phosphate compound containing lithium and one or two or more transition metal elements as constituent elements. The type of the transition metal element is not particularly limited, and examples thereof include cobalt (Co), nickel (Ni), manganese (Mn), and iron (Fe).

The lithium transition metal complex oxide is, for example, a complex oxide composed of Li _x M1O ₂ And Li _y M2O ₄ The compounds shown, and the like. The lithium transition metal phosphate compound is, for example, a compound formed from Li _z M3PO ₄ The compounds shown, and the like. Wherein M1, M2 and M3 are respectively one or more than two transition metal elements. The values of x, y and z are arbitrary.

Specifically, the lithium transition metal composite oxide is, for example, LiCoO ₂ 、LiNiO ₂ 、LiVO ₂ 、LiCrO ₂ 、LiMn ₂ O ₄ 、LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ And LiNi _0.5 Mn _1.5 O ₄ And the like. Further, the lithium transition metal phosphate compound is, for example, LiFePO ₄ 、LiCoPO ₄ And LiMnPO ₄ And the like. Lithium transition metal composite oxide (particularly LiCoO) ₂ ) The additive elements may be contained in a trace amount (about several%). Examples of the additive element include at least one element selected from the group consisting of Al, Mg, Ni, Mn, Ti, Zr, boron, vanadium, chromium, iron, copper, zinc, molybdenum, tin, tungsten, zirconium, yttrium, niobium, calcium, strontium, bismuth, sodium, potassium, and silicon.

The positive electrode active material capable of intercalating and deintercalating sodium ions may be at least one selected from the group consisting of a sodium-containing phosphate compound having a NASICON-type structure, a sodium-containing phosphate compound having an olivine-type structure, a sodium-containing layered oxide, a sodium-containing oxide having a spinel-type structure, and the like.

The content of the positive electrode active material in the positive electrode layer 10A is usually 50 mass% or more (i.e., 50 to 100 mass%), particularly 60 to 90 mass%, with respect to the total amount of the positive electrode layer. The positive electrode layer may contain two or more positive electrode active materials, and in this case, the total content thereof may be within the above range.

The conductive carbon material contained in positive electrode layer 10A is a carbon atom-containing material having conductivity. Examples of the conductive carbon material include at least one carbon material selected from the group consisting of columnar carbon materials, granular carbon materials, hollow carbon materials, and sheet carbon materials. From the viewpoint of more sufficiently preventing the decrease in the theoretical capacity ratio, the capacity characteristics, and the load characteristics, the conductive carbon material is preferably at least one carbon material selected from the group consisting of columnar carbon materials and granular carbon materials, and more preferably at least one carbon material selected from the group consisting of columnar carbon materials.

The columnar carbon material is a carbon material having a long and thin shape, in other words, a carbon material having an external shape extending in one direction. In detail, the columnar carbon material is a carbon material as follows: when the maximum length of two points connecting the cross section of the carbon material when the thickest part of the columnar shape is cut into a circular piece is defined as r, and the height (for example, the long dimension) of the columnar shape is defined as L, L/r is 3 or more. The columnar carbon material has an L/r of usually 3 to 3000, preferably 10 to 500, more preferably 20 to 80, and even more preferably 30 to 50, from the viewpoint of more sufficiently preventing the reduction of the theoretical capacity ratio, the capacity characteristics, and the load characteristics.

The r of the columnar carbon material is not particularly limited, and is preferably 5 to 500nm, more preferably 20 to 400nm, and further preferably 100 to 300nm, from the viewpoint of more sufficiently preventing the decrease in the theoretical capacity ratio, the capacity characteristics, and the load characteristics.

The L of the columnar carbon material is not particularly limited, but is preferably 2 to 20 μm, and more preferably 3 to 20 μm, from the viewpoint of more sufficiently preventing the decrease in the theoretical capacity ratio, the capacity characteristics, and the load characteristics.

In the present specification, L and r are average values of values determined for arbitrary 100 carbon materials by electron microscope observation. As described above, L is the height of the columnar shape, in other words, the maximum length in the longitudinal direction. As described above, r is the maximum length of two points connecting the cross section of the carbon material (particularly, the outer edge thereof) when the thickest part of the columnar shape is cut into a circular piece, in other words, the maximum length in the direction perpendicular to the longitudinal direction.

The columnar carbon material may have a hollow form or may have a solid form. The columnar carbon material contains a fibrous carbon material.

As a commercially available product of carbon nanotubes which can be used as a columnar carbon material, for example, VGCF available from Showa Denko K.K. ^(R) -H (r 150nm, L/r 40), SHENZHEN SUSN SINOTECH NEW MATERIALS co, LTD GCNTs 10(r 10-20 nm, L/r 250-1200), SHENZHEN SUSN SINOTECH NEW MATERIALS co, LTD GCNTs40(r 35-50 nm, L/r 100-400), and the like.

The granular carbon material is a substantially spherical conductive carbon material and does not have a hollow shell structure. Specifically, the particulate carbon material has an average particle diameter of 10 to 90nm, and from the viewpoint of more sufficiently preventing the reduction of the theoretical capacity ratio, the capacity characteristics, and the load characteristics, the average particle diameter is preferably 20 to 80nm, more preferably 30 to 70nm, and still more preferably 40 to 60 nm.

The average particle diameter of the particulate carbon material is an average primary particle diameter, which is an average value of values measured for any 100 carbon materials by electron microscope observation. The average particle diameter is an average of the maximum lengths of the respective particles.

As the particulate carbon material, for example, carbon black or acetylene black can be used.

Commercially available carbon black products include, for example, SuperC45 and SuperC65 manufactured by TIMCAL corporation.

As a commercial product of acetylene black, for example, DENKABLACK manufactured by DENKA K.K. ^(R) And the like.

The hollow carbon material is a substantially spherical conductive carbon material and has a hollow shell structure. Specifically, the hollow carbon material has an average particle diameter of 10 to 80nm, and from the viewpoint of more sufficiently preventing the decrease in the theoretical capacity ratio, the capacity characteristics, and the load characteristics, the average particle diameter is preferably 20 to 70nm, and more preferably 30 to 50 nm.

The average particle diameter of the hollow carbon material is a value measured by the same method as the average particle diameter of the particulate carbon material.

As the hollow carbon material, ketjen black, for example, can be used.

Examples of commercially available ketjen black products include carboncep manufactured by LION SPECIALTY chemcals co.

The flaky carbon material is a flaky, scaly or flaky conductive carbon material. Specifically, the flaky carbon material has an average thickness of 30 to 1000nm and a maximum length of 1 to 15 μm. From the viewpoint of more sufficiently preventing the reduction of the theoretical capacity ratio, the capacity characteristics, and the load characteristics, the average thickness is preferably 60 to 500 nm.

The average thickness of the flaky carbon material is an average value of thicknesses measured for arbitrary 100 carbon materials by electron microscope observation. The average thickness is the average of the minimum lengths of the individual particles.

The maximum length of the flaky carbon material is an average value of maximum lengths determined for any 100 carbon materials by electron microscope observation.

As the sheet-like carbon material, for example, natural graphite, artificial graphite, and graphene can be used.

Examples of commercially available natural graphite include flake graphite J-CPB manufactured by Nippon graphite industries, Ltd.

As a commercially available product of artificial Graphite, for example, KS-6 and KS-15, available from Imerys Graphite & Carbon Co.

The content of the conductive carbon material in the positive electrode layer 10A is not particularly limited, and is usually 0.5 mass% or more and 25 mass% or less with respect to the total amount of the positive electrode layer. In the case where the positive electrode layer contains two or more kinds of conductive carbon materials, their total content may be within the above range unless otherwise specified.

From the viewpoint of more sufficiently preventing the decrease in the theoretical capacity ratio, the capacity characteristics, and the load characteristics, in a preferred embodiment (hereinafter, sometimes simply referred to as "embodiment a"), the conductive carbon material in positive electrode layer 10A contains one or more carbon materials selected from the group consisting of columnar carbon materials and granular carbon materials, and the content of the conductive carbon material satisfies at least one of the following conditions a1 or a 2:

condition a 1: the content of the columnar carbon material is 0.5 mass% or more and 12 mass% or less with respect to the total amount of the positive electrode layer;

condition a 2: the content of the particulate carbon material is 1.5 mass% or more and 8 mass% or less with respect to the total amount of the positive electrode layer.

In embodiment a, for example, when the conductive carbon material includes one of a columnar carbon material and a granular carbon material, the content of the conductive carbon material satisfies one of the above-described conditions a1 or a 2. That is, the content of the conductive carbon material satisfies the above condition a1 in the case where the conductive carbon material contains a columnar carbon material, and satisfies the above condition a2 in the case where the conductive carbon material contains a granular carbon material.

For example, when the conductive carbon material contains both a columnar carbon material and a granular carbon material, the content of the conductive carbon material may satisfy at least one of the above conditions a1 and a2, and usually satisfies both the above conditions a1 and a 2.

In this embodiment a, the positive electrode layer is not prevented from containing a conductive carbon material (sometimes referred to as "other conductive carbon material x") other than the columnar carbon material and the granular carbon material, and in this case, the content of the other conductive carbon material x is not particularly limited, and may be, for example, 10 mass% or less, particularly 5 mass% or less, and usually 0 mass% with respect to the total amount of the positive electrode layer.

In a more preferred embodiment (hereinafter, may be simply referred to as "embodiment B") from the viewpoint of more sufficiently preventing the decrease in the theoretical capacity ratio, the capacity characteristics, and the load characteristics, the conductive carbon material in positive electrode layer 10A contains one or more carbon materials selected from the group consisting of columnar carbon materials and granular carbon materials, and the content of the conductive carbon material satisfies at least one of the following conditions B1 or B2:

condition B1: the content of the columnar carbon material is 0.5 mass% or more and 12 mass% or less with respect to the total amount of the positive electrode layer;

condition B2: the content of the particulate carbon material is 2.5 mass% or more and 5.5 mass% or less with respect to the total amount of the positive electrode layer.

In embodiment B, for example, when the conductive carbon material includes one of a columnar carbon material and a granular carbon material, the content of the conductive carbon material satisfies one of the above conditions B1 and B2. That is, the content of the conductive carbon material satisfies the above condition B1 when the conductive carbon material contains a columnar carbon material, and satisfies the above condition B2 when the conductive carbon material contains a granular carbon material.

For example, in the case where the conductive carbon material contains both a columnar carbon material and a granular carbon material, the content of the conductive carbon material may satisfy at least one of the above conditions B1 or B2, and usually satisfies both the above conditions B1 and B2.

In embodiment B, the positive electrode layer is not prevented from containing a conductive carbon material (sometimes referred to as "other conductive carbon material x") other than the columnar carbon material and the granular carbon material, and in this case, the content of the other conductive carbon material x is not particularly limited, and may be, for example, 10 mass% or less, particularly 5 mass% or less, and usually 0 mass% with respect to the total amount of the positive electrode layer.

From the viewpoint of more sufficiently preventing the decrease in the theoretical capacity ratio, the capacity characteristics, and the load characteristics, in a more preferred embodiment (hereinafter, sometimes simply referred to as "embodiment C"), the conductive carbon material in positive electrode layer 10A contains one or more carbon materials selected from the group consisting of columnar carbon materials, and the content of the conductive carbon material satisfies the following condition C1:

condition C1: the content of the columnar carbon material is 0.5 mass% or more and 4 mass% or less with respect to the total amount of the positive electrode layer.

In embodiment C, the positive electrode layer does not prevent the conductive carbon material other than the columnar carbon material (may be referred to as "other conductive carbon material y"), and in this case, the content of the other conductive carbon material y is not particularly limited, and may be, for example, 10 mass% or less, particularly 5 mass% or less, and usually 0 mass% with respect to the total amount of the positive electrode layer.

In the method for detecting the conductive carbon material, the presence of the conductive carbon material can be confirmed by observing the positive electrode layer by SEM.

As for the method for quantifying the conductive carbon material, the conductive carbon material can be quantified by performing TG-DTA measurement of the positive electrode layer.

The solid electrolyte that can be contained in positive electrode layer 10A can be selected from, for example, the same materials as those contained in the solid electrolyte layer described later.

The content of the solid electrolyte in the positive electrode layer 10A is not particularly limited, and is usually 10 mass% or more and 40 mass% or less, particularly 20 mass% or more and 40 mass% or less, with respect to the total amount of the positive electrode layer. The positive electrode layer may contain two or more kinds of solid electrolytes, in this case, as long as their total content is within the above range.

Positive electrode layer 10A may further contain a sintering aid. The sintering aid may be at least one selected from the group consisting of lithium oxide, sodium oxide, potassium oxide, boron oxide, silicon oxide, bismuth oxide, and phosphorus oxide.

The thickness of positive electrode layer 10A is not particularly limited, and may be, for example, 2 μm or more and 100 μm or less, particularly 5 μm or more and 50 μm or less.

Positive electrode current collecting portion 11 is a connection portion (or connection layer) between positive electrode layer 10A and positive electrode terminal 40A, and is formed at least by containing a conductive material. Positive electrode collector 11 may include a solid electrolyte. In a preferred embodiment, the positive electrode current collecting portion is formed of a sintered body containing at least a conductive material and a solid electrolyte.

The conductive material that can be contained in positive electrode current collector 11 is generally a material having relatively high conductivity, and for example, at least one selected from the group consisting of carbon materials, silver, palladium, gold, platinum, aluminum, copper, and nickel may be used.

The content of the conductive material in the positive electrode current collecting portion 11 is usually 30 mass% or more (i.e., 30 mass% or more and 100 mass% or less), and particularly 60 mass% or more and 90 mass% or less, with respect to the total amount of the positive electrode current collecting portion. The positive electrode current collector may contain two or more kinds of conductive materials, in this case, as long as the total content thereof is within the above range.

The solid electrolyte included in the positive electrode current collector portion 11 may be selected from, for example, the same materials as those included in a solid electrolyte layer described later.

The content of the solid electrolyte in the positive electrode current collecting portion 11 is not particularly limited, and is usually 10 mass% or more and 60 mass% or less, particularly 20 mass% or more and 40 mass% or less, with respect to the total amount of the positive electrode current collecting portion. The positive electrode current collector may contain two or more types of solid electrolytes, in this case, as long as the total content thereof is within the above range.

When the positive electrode current collecting portion has the form of a sintered body, the positive electrode current collecting portion 11 may further contain a sintering aid. The sintering agent contained in the positive electrode current collector may be selected from, for example, the same materials as the sintering aid contained in the positive electrode layer.

The thickness of positive electrode collector portion 11 is generally the same as that of positive electrode layer 10A, and may be selected from the range of thicknesses equal to that of positive electrode layer 10A.

(negative electrode layer)

Negative electrode layer 10B may have an end surface current collecting structure, or may have a main surface current collecting structure. From the viewpoint of further improving the capacity density (e.g., energy density), negative electrode layer 10B preferably has an end surface current collecting structure.

Negative electrode layer 10B having the end surface current collecting structure means that negative electrode layer 10B has a structure in which current is collected at end surface 10B1 (particularly, only the end surface) of the negative electrode layer. Specifically, for example, as shown in fig. 2 and 3, the negative electrode layer 10B may be directly electrically connected to the negative electrode terminal 40B at an end face 10B1 (particularly, only an end face) of the negative electrode layer 10B, or may be in contact with a negative electrode current collecting portion (not shown) at an end face 10B1 (particularly, only an end face) of the negative electrode layer 10B and electrically connected to the negative electrode terminal via the negative electrode current collecting portion. From the viewpoint of improving the current collection efficiency, as shown in fig. 2 and 3, negative electrode layer 10B is preferably electrically connected directly to negative electrode terminal 40B at end face 10B1 (particularly, only the end face) of negative electrode layer 10B without passing through the negative current collection portion.

In the end surface current collecting structure of the negative electrode layer 10B, when the negative electrode layer 10B is electrically connected to the negative electrode terminal via the negative electrode current collecting portion (not shown), the negative electrode layer 10B and the negative electrode current collecting portion are in contact with each other at the end surfaces, and as a result, they have a structure in which they are adjacent to each other in a direction perpendicular to the stacking direction when viewed in cross section. The negative electrode layer and the negative electrode current collector have a structure in which they are adjacent to each other in a direction perpendicular to the stacking direction in a plan view.

The negative electrode layer having a main surface current collecting structure means that the negative electrode layer has a structure that collects current on the main surface of the negative electrode layer. Specifically, the negative electrode layer is in contact with a negative electrode current collector (particularly, a negative electrode current collector layer) on a main surface of the negative electrode layer, and is electrically connected to a negative electrode terminal via the negative electrode current collector. In the main surface current collecting structure of the negative electrode layer, the negative electrode layer is laminated on the main surface of the negative electrode current collector (particularly, the negative electrode current collecting layer). The main surface is a surface having a relatively large area, and more specifically, an upper surface and/or a lower surface perpendicular to the stacking direction. Collecting current on the main surface means that electrons come in and go out from the main surface.

Negative electrode layer 10B is an electrode layer containing at least a negative electrode active material. Negative electrode layer 10B may further contain a solid electrolyte. In a preferred embodiment, the negative electrode layer is composed of a sintered body containing at least a negative electrode active material and a solid electrolyte.

The negative electrode active material contained in the negative electrode layer 10B is a material participating in the transfer of electrons in the solid-state battery. Charge and discharge are performed by carrying out movement (conduction) of ions between the positive electrode layer and the negative electrode layer via the solid electrolyte and transfer of electrons between the positive electrode layer and the negative electrode layer via an external circuit. The negative electrode layer is particularly preferably a layer capable of inserting and extracting lithium ions or sodium ions (particularly lithium ions).

Examples of the negative electrode active material include carbon materials, metal materials, lithium alloys, and lithium-containing compounds.

Specifically, examples of the carbon material include graphite, easily graphitizable carbon, hardly graphitizable carbon, mesocarbon microbeads (MCMB), highly oriented graphite (HOPG), and the like. The carbon material as the negative electrode active material may be a sheet-like carbon material that can be used as the conductive carbon material of the positive electrode layer 10A.

The metal-based material is a generic term for a material containing, as a constituent element, any one or two or more of a metal element and a semimetal element capable of forming an alloy with lithium. The metallic material may be a simple substance, an alloy, or a compound. The purity of the simple substance described herein is not necessarily limited to 100%, and therefore the simple substance may contain a trace amount of impurities.

Examples of the metal element and the semimetal element include silicon (Si), tin (Sn), aluminum (Al), indium (In), magnesium (Mg), boron (B), gallium (Ga), germanium (Ge), lead (Pb), bismuth (Bi), cadmium (Cd), titanium (Ti), chromium (Cr), iron (Fe), niobium (Nb), molybdenum (Mo), silver (Ag), zinc (Zn), hafnium (Hf), zirconium (Zr), yttrium (Y), palladium (Pd), and platinum (Pt).

Specifically, the metallic material is, for example, Si, Sn, SiB ₄ 、TiSi ₂ 、SiC、Si ₃ N ₄ 、SiO _v (0＜v≤2)、LiSiO、SnO _w (0＜w≤2)SnSiO ₃ LiSnO and Mg ₂ Sn, and the like.

The lithium-containing compound is, for example, a lithium transition metal composite oxide or the like. The definition relating to the lithium transition metal composite oxide is as described above. Specifically, the lithium transition metal composite oxide is, for example, Li ₃ V ₂ (PO ₄ ) ₃ 、Li ₃ Fe ₂ (PO ₄ ) ₃ 、Li ₄ Ti ₅ O ₁₂ 、LiTi ₂ (PO ₄ ) ₃ And LiCuPO ₄ And the like.

The negative electrode active material capable of intercalating and deintercalating sodium ions may be at least one selected from the group consisting of a sodium-containing phosphate compound having a NASICON-type structure, a sodium-containing phosphate compound having an olivine-type structure, a sodium-containing oxide having a spinel-type structure, and the like.

The content of the negative electrode active material in the negative electrode layer 10B is usually 50 mass% or more (i.e., 50 mass% or more and 100 mass% or less), and particularly 60 mass% or more and 90 mass% or less, with respect to the total amount of the negative electrode layer. The negative electrode layer may contain two or more negative electrode active materials, and in this case, the total content thereof may be within the above range.

The solid electrolyte that can be contained in the negative electrode layer 10B may be selected from, for example, the same materials as those contained in a solid electrolyte layer described later.

The content of the solid electrolyte in the negative electrode layer 10B is not particularly limited, and is usually 10 mass% or more and 40 mass% or less, particularly 20 mass% or more and 40 mass% or less, with respect to the total amount of the negative electrode layer. The negative electrode layer may contain two or more kinds of solid electrolytes, and in this case, the total content thereof may be within the above range.

Negative electrode layer 10B may further contain a sintering aid. The sintering aid may be the same material as the sintering aid included in positive electrode layer 10A.

The thickness of negative electrode layer 10B is not particularly limited, and may be, for example, 2 μm or more and 100 μm or less, particularly 5 μm or more and 50 μm or less.

When negative electrode layer 10B is electrically connected to negative electrode terminal 40B via the negative electrode current collecting portion, the negative electrode current collecting portion may be made of the same constituent material as that of positive electrode current collecting portion 11.

(solid electrolyte layer)

The solid electrolyte layer 20 is a layer including at least a solid electrolyte. In a preferred embodiment, the solid electrolyte layer is made of a sintered body containing at least a solid electrolyte.

The solid electrolyte constituting the solid electrolyte layer 20 is a material capable of conducting lithium ions or sodium ions (particularly lithium ions). The solid electrolyte forms a layer capable of conducting lithium ions or sodium ions (particularly lithium ions) particularly between the positive electrode layer and the negative electrode layer. The solid electrolyte may be provided at least between the positive electrode layer and the negative electrode layer. That is, the solid electrolyte may be present around the positive-electrode layer and/or the negative-electrode layer so as to be exposed between the positive-electrode layer and the negative-electrode layer. Specific examples of the solid electrolyte include one or two or more of a crystalline solid electrolyte and a glass ceramic solid electrolyte.

The crystalline solid electrolyte is a crystalline electrolyte. Specifically, the crystalline solid electrolyte is, for example, an inorganic material such as a sulfide or an oxide, or a polymer material. Sulfides being, for example, Li ₂ S-P ₂ S ₅ 、Li ₂ S-SiS ₂ -Li ₃ PO ₄ 、Li ₇ P ₃ S ₁₁ 、Li _3.25 Ge _0.25 P _0.75 S and Li ₁₀ GeP ₂ S ₁₂ And the like. The oxide being, for example, Li _x M _y (PO ₄ ) ₃ (1. ltoreq. x.ltoreq.2, 1. ltoreq. y.ltoreq.2, M is at least one member selected from the group consisting of Ti, Ge, Al, Ga and Zr), Li ₇ La ₃ Zr ₂ O ₁₂ 、Li _6.75 La ₃ Zr _1.75 Nb _0.25 O ₁₂ 、Li ₆ BaLa ₂ Ta ₂ O ₁₂ 、Li _1+x Al _x Ti _2-x (PO ₄ ) ₃ 、La _2/3-x Li _3x TiO ₃ 、Li _1.2 Al _0.2 Ti _1.8 (PO ₄ ) ₃ 、La _0.55 Li _0.35 TiO ₃ And Li ₇ La ₃ Zr ₂ O ₁₂ And the like. The polymer material is, for example, polyethylene oxide (PEO) or the like.

The glass ceramic solid electrolyte is an electrolyte in which an amorphous substance and a crystal are mixed. The glass ceramic solid electrolyte is, for example, an oxide containing lithium (Li), silicon (Si) and boron (B) as constituent elements, and more specifically, contains lithium oxide (Li) ₂ O), silicon oxide (SiO) ₂ ) And boron oxide (B) ₂ O ₃ ) And the like. The proportion of the content of lithium oxide to the total content of lithium oxide, silicon oxide, and boron oxide is not particularly limited, and is, for example, 40 mol% or more and 73 mol% or less. The proportion of the content of silicon oxide to the total content of lithium oxide, silicon oxide, and boron oxide is not particularly limited, and is, for example, 8 mol% or more and 40 mol% or less. The proportion of the content of boron oxide to the total content of lithium oxide, silicon oxide and boron oxide is not particularly limited, and is, for example, 10 mol% or more and 50 mol%The following. In order to measure the content of each of lithium oxide, silicon oxide, and boron oxide, a glass ceramic-based solid electrolyte is analyzed using, for example, inductively coupled plasma emission spectroscopy (ICP-AES).

Examples of the solid electrolyte capable of conducting sodium ions include sodium-containing phosphate compounds having a NASICON structure, oxides having a perovskite structure, and oxides having a garnet-type or garnet-like structure. The sodium-containing phosphoric acid compound having a NASICON structure includes Na _x M _y (PO ₄ ) ₃ (1. ltoreq. x.ltoreq.2, 1. ltoreq. y.ltoreq.2, M is at least one selected from the group consisting of Ti, Ge, Al, Ga and Zr).

The solid electrolyte layer 20 may further include a sintering aid. The sintering aid may be the same material as the sintering aid included in positive electrode layer 10A.

The thickness of the solid electrolyte layer is not particularly limited, and may be, for example, 1 μm or more and 40 μm or less, particularly 1 μm or more and 15 μm or less.

(electrode separating part)

The solid-state battery 200 of the present invention generally further has an electrode separating portion (also referred to as a "blank layer" or a "margin portion") 30(30A, 30B).

By disposing electrode separating portion 30A (positive electrode separating portion) around positive electrode layer 10A, positive electrode layer 10A is separated from negative electrode terminal 40B. In addition, by disposing electrode separator 30B (negative electrode separator) around negative electrode layer 10B, negative electrode layer 10B is separated from positive electrode terminal 40A. Although not particularly limited, the electrode separating portion 30 is preferably formed of, for example, a solid electrolyte, an insulating material, a mixture thereof, or the like.

The solid electrolyte that can constitute the electrode separating portion 30 can use the same material as the solid electrolyte that can constitute the solid electrolyte layer.

The insulating material that can constitute the electrode separating portion 30 may be a non-conductive material. Although not particularly limited, the insulating material may be a glass material, a ceramic material, or the like. As the insulating materialThe frit may be, for example, a glass material. The glass material is not particularly limited, and may include at least one selected from the group consisting of soda lime glass, potassium glass, borate glass, borosilicate barium glass, zinc borate glass, barium borate glass, borosilicate bismuth glass, bismuth zinc borate glass, bismuth silicate glass, phosphate glass, aluminum phosphate glass, and zinc phosphate glass. Although not particularly limited, the ceramic material may be selected from the group consisting of alumina (Al) ₂ O ₃ ) Boron Nitride (BN), silicon dioxide (SiO) ₂ ) Silicon nitride (Si) ₃ N ₄ ) Zirconium oxide (ZrO) ₂ ) Aluminum nitride (AlN), silicon carbide (SiC) and barium titanate (BaTiO) ₃ ) At least one of the group consisting of.

(terminal)

In the solid-state battery 200 of the present invention, terminals (external terminals) 40(40A, 40B) are generally provided. In particular, the positive and negative terminals 40A and 40B are provided in pairs on the side surfaces of the solid-state battery. More specifically, a positive electrode-side terminal 40A connected to the positive electrode layer 10A and a negative electrode-side terminal 40B connected to the negative electrode layer 10B are provided in a pair. The terminals 40(40A, 40B) are preferably made of a material having high electrical conductivity. The material of the terminal 40 is not particularly limited, and at least one conductive material selected from the group consisting of silver, gold, platinum, aluminum, copper, tin, and nickel can be used. The positive electrode terminal 40A and the negative electrode terminal 40B are formed on the opposite side surfaces of the solid-state battery stack 100, which can be understood as the end surfaces of the solid-state battery stack, and these terminals can be understood as the electrodes of the battery in relation to the outside of the battery. Therefore, the positive electrode terminal 40A and the negative electrode terminal 40B can be referred to as a positive electrode end face electrode and a negative electrode end face electrode, respectively.

(outer layer Material)

The solid-state battery 200 of the present invention also typically has an outer layer material 60.

The outer layer material 60 may be formed generally on the outermost side of the solid state battery for electrical, physical and/or chemical protection. The material constituting the outer layer material 60 is preferably excellent in insulation, durability and/or moisture resistance and is environmentally safe. For example, glass, ceramics, thermosetting resins, photocurable resins, and mixtures thereof may be used.

The glass that can constitute the material of the outer layer can be the same as the glass material that can constitute the electrode separating portion.

The ceramic material that can constitute the outer layer material can use the same material as the ceramic material that can constitute the electrode separating portion.

[ method for producing solid-State Battery ]

The solid-state battery of the present invention can be manufactured by a printing method such as a screen printing method, a green sheet method using a green sheet, or a composite method thereof. Hereinafter, a case where the printing method and the green sheet method are used will be described in detail for understanding the present invention, but the present invention is not limited to this method.

(Process for Forming solid Battery Stack precursor)

In this step, for example, several pastes such as a positive electrode layer paste, a negative electrode layer paste, a solid electrolyte layer paste, a positive electrode current collecting portion paste, an electrode separating portion paste, and an outer layer material paste are used as the inks. That is, the paste is applied and dried by a printing method, thereby forming a solid-state battery stack precursor having a predetermined structure on the supporting substrate.

When printing, the printing layers are sequentially laminated in a predetermined thickness and a pattern shape, whereby a solid-state battery laminate precursor corresponding to the structure of a predetermined solid-state battery can be formed on the substrate. The type of pattern forming method is not particularly limited as long as it is a method capable of forming a predetermined pattern, and is, for example, any one or two or more of a screen printing method, a gravure printing method, and the like.

The paste can be prepared by wet-mixing a predetermined constituent material for each layer selected from the group consisting of positive electrode active material particles, negative electrode active material particles, conductive material, solid electrolyte material, current collector material, insulating material, sintering aid, and other materials with an organic vehicle in which an organic material is dissolved in a solvent.

The positive electrode layer paste contains, for example, positive electrode active material particles, a conductive carbon material, a solid electrolyte material, an organic material, a solvent, and, if necessary, a sintering aid.

The negative electrode layer paste contains, for example, negative electrode active material particles, a solid electrolyte material, an organic material, a solvent, and a sintering aid as needed.

The paste for the solid electrolyte layer contains, for example, a solid electrolyte material, an organic material, a solvent, and a sintering aid as needed.

The positive electrode current collecting portion paste contains a conductive material, an organic material, a solvent, and a sintering aid as needed.

The paste for the electrode separation portion contains, for example, a solid electrolyte material, an insulating material, an organic material, a solvent, and a sintering aid as needed.

The paste for the outer layer material contains, for example, an insulating material, an organic material, a solvent, and a sintering aid as needed.

The organic material contained in the paste is not particularly limited, and at least one polymer material selected from the group consisting of polyvinyl acetal resin, cellulose resin, polyacrylic resin, polyurethane resin, polyvinyl acetate resin, polyvinyl alcohol resin, and the like can be used.

The type of the solvent is not particularly limited, and examples thereof include one or two or more of organic solvents such as butyl acetate, N-methyl-pyrrolidone, toluene, terpineol, and N-methyl-pyrrolidone.

A medium can be used for the wet mixing, and specifically, a ball mill method, a viscous mill method, or the like can be used. On the other hand, a wet mixing method using no medium may be used, and a sand milling method, a high-pressure homogenizer method, a kneading dispersion method, or the like can be used.

The supporting base is not particularly limited as long as it is a supporting body capable of supporting each paste layer, and is, for example, a release film having a release treatment applied to one surface thereof. Specifically, a substrate made of a polymer material such as polyethylene terephthalate can be used. When the paste layer is supplied to the firing step while being held on the substrate, a substrate exhibiting heat resistance to the firing temperature may be used as the substrate.

As another method, green sheets may be formed from the pastes, and the obtained green sheets may be stacked to produce a solid-state battery stack precursor.

Specifically, the support substrate coated with each paste is dried on a hot plate heated to 30 ℃ or higher and 50 ℃ or lower, thereby forming a positive electrode layer green sheet, a negative electrode layer green sheet, a solid electrolyte layer green sheet, a positive electrode current collector green sheet, an electrode separator green sheet, and/or an outer layer material green sheet, etc., each having a predetermined shape and thickness, on each support substrate (for example, PET film).

Subsequently, each green sheet was peeled off from the substrate. After the peeling, the green sheets of the respective constituent elements are stacked in order along the stacking direction, thereby forming a solid-state battery stack precursor. After the stacking, a solid electrolyte layer, an insulating layer, a protective layer, and/or the like may be provided on the side region of the electrode green sheet by screen printing.

(firing Process)

In the firing step, the solid-state battery stack precursor is fired. Although the firing is only exemplified, the organic material is removed by heating in a nitrogen atmosphere containing oxygen or in the atmosphere, for example, at 200 ℃ or higher, and then heating in a nitrogen atmosphere or in the atmosphere, for example, at 300 ℃ or higher. The firing may be performed while pressurizing the solid-state battery stack precursor in the stacking direction (in some cases, the stacking direction and a direction perpendicular to the stacking direction).

By performing such firing, a solid-state battery laminate is formed, and a desired solid-state battery can be finally obtained.

(Process for Forming Positive electrode terminal and negative electrode terminal)

For example, the positive electrode terminal is bonded to the solid cell laminate using a conductive adhesive, and the negative electrode terminal is bonded to the solid cell laminate using a conductive adhesive. In this way, the positive electrode terminal and the negative electrode terminal are attached to the solid-state battery laminate, respectively, and the solid-state battery is completed.

The embodiments of the present invention have been described above, but only typical examples thereof are illustrated. Therefore, those skilled in the art will readily understand that the present invention is not limited thereto, and various aspects can be considered within a range not changing the gist of the present invention.

Examples

< conductive Material >

The following materials were used as the conductive material.

(columnar conductive carbon material)

Carbon nanotube A: SHENZHEN SUSN SINOTECH NEW MATERIALS CO., LTD GCNT s10(r 10 ~ 20nm, L/r 250 ~ 1200)

And (3) carbon nano tube B: SHENZHEN SUSN SINOTECH NEW MATERIALS CO., LTD GCNT s40(r 35 ~ 50nm, L/r 100 ~ 400)

Carbon nanotube C: VGCF manufactured by Showa Denko K.K ^(R) -H(r＝150nm，L/r＝40)

(granular conductive carbon Material)

DENKA BLACK (acetylene BLACK): DENKA BLACK manufactured by DENKA K.K ^(R) Average particle diameter of 48nm

(hollow conductive carbon material)

Ketjen black: CarbonECP manufactured by LION SPECIATY CHEMICALS, having an average particle diameter of 40nm

(sheet-like conductive carbon Material)

KS-6 (Artificial graphite): KS-6 manufactured by Imerys, Graphite & Carbon company, having an average thickness of 100nm and a maximum length of about 3 to 6 μm

< example 1 >

(Process for producing Green sheet for producing solid electrolyte layer)

First, as a solid electrolyte, lithium-containing oxide glass and an acrylic binder were mixed at a mass ratio of lithium-containing oxide glass to acrylic binder of 70: 30. As the lithium-containing oxide glass, lithium-containing oxide glass having a composition of Li 2O: SiO 2: B2O3 of 60: 10: 30 (mol%) was used. Subsequently, the obtained mixture was mixed with butyl acetate to make the solid content 30 mass%, and then stirred with zirconia balls having a diameter of 5mm for 4 hours to obtain a paste for producing a solid electrolyte layer. Next, this paste was applied to a release film and dried at 80 ℃ for 10 minutes, thereby producing a solid electrolyte layer-producing green sheet as a solid electrolyte layer precursor.

(production of Green sheet for production of Positive electrode active Material layer)

First, lithium cobaltate (LiCoO2) as a positive electrode active material and lithium-containing oxide glass as a solid electrolyte were mixed at a mass ratio of lithium cobaltate to lithium-containing oxide glass of 70: 30. As the lithium-containing oxide glass, a glass having a composition of Li2O, SiO2, B2O3 of 60: 10: 30 (mol%) of lithium oxide-containing glass. Next, the conductive material is mixed so that the ratio of the resulting mixture to the conductive material is 100-x: x. The obtained mixture was mixed with an acrylic binder at a mass ratio of 70: 30 (lithium cobaltate + lithium-containing oxide glass + conductive aid) to the acrylic binder, and then mixed with butyl acetate to obtain a solid content of 30 mass%. Then, the obtained mixture was stirred with zirconia balls having a diameter of 5mm for 4 hours, thereby obtaining a paste for producing a positive electrode active material layer. Next, this paste was applied to a release film and dried at 80 ℃ for 10 minutes, thereby producing a green sheet for producing a positive electrode active material layer as a positive electrode layer precursor.

(Process for producing Green sheet for producing negative electrode active Material layer)

First, carbon powder (KS 6, manufactured by timal corporation) as a negative electrode active material and lithium-containing oxide glass as a solid electrolyte were mixed at a mass ratio of 70: 30. As the lithium-containing oxide glass, lithium-containing oxide glass having a composition of Li 2O: SiO 2: B2O3 of 60: 10: 30 (mol%) was used. Next, the obtained mixture was mixed with an acrylic binder at a mass ratio of the mixture (carbon powder + lithium-containing oxide glass) to the acrylic binder of 70: 30, and then mixed with butyl acetate so that the solid content became 30 mass%. Then, the obtained mixture was stirred with zirconia balls having a diameter of 5mm for 4 hours, thereby obtaining a negative electrode active material layer-producing paste. Next, this paste was applied to a release film and dried at 80 ℃ for 10 minutes, thereby producing a green sheet for producing a negative electrode active material layer as a negative electrode active material layer precursor.

(Process for producing Green sheet for producing Positive electrode Current collecting portion)

First, carbon powder (KS 6, manufactured by timal corporation) as a conductive material and lithium-containing oxide glass as a solid electrolyte were mixed at a mass ratio of 70: 30 of carbon powder to lithium-containing oxide glass. As the lithium-containing oxide glass, lithium-containing oxide glass having a composition of Li 2O: SiO 2: B2O3 of 60: 10: 30 (mol%) was used. Next, the obtained mixture was mixed with an acrylic binder at a mass ratio of the mixture (carbon powder + lithium-containing oxide glass) to the acrylic binder of 70: 30, and then mixed with butyl acetate so that the solid content became 30 mass%. Then, the obtained mixture was stirred with zirconia balls having a diameter of 5mm for 4 hours to obtain a paste for producing a positive electrode current collecting portion. Next, this paste was applied to a release film and dried at 80 ℃ for 10 minutes, thereby producing a green sheet for producing a positive current collecting portion, which was a precursor of the positive current collecting portion.

(Process for producing Green sheet for producing outer layer Material)

First, alumina particle powder (AHP 300, manufactured by japan light metal) as particle powder and lithium-containing oxide glass (B) as a solid electrolyte were mixed at a mass ratio of 50: 50 of alumina particle powder to lithium-containing oxide glass (B). Next, the obtained mixture was mixed with an acrylic binder at a mass ratio of the mixture (alumina particle powder + lithium-containing oxide glass (B)): acrylic binder of 70: 30, and then mixed with butyl acetate so that the solid content became 30 mass%. Then, the obtained mixture was stirred with zirconia balls having a diameter of 5mm for 4 hours to obtain a paste for preparing a main surface exterior material. Next, this paste was applied to a release film and dried at 80 ℃ for 10 minutes, thereby producing a green sheet for forming an outer layer material as a precursor of the main surface outer layer material.

(Process for producing Green sheet for producing electrode separating portion)

Similarly to the "step of preparing a green sheet for preparing an outer layer material" described above, a green sheet for preparing an electrode separating portion was prepared as an electrode separating portion precursor.

(Process for producing laminate)

Using the green sheets obtained as described above, a laminate having the structure shown in fig. 1 and 2 was produced as follows. First, each green sheet was processed into a shape shown in fig. 1 and 2, and then released from a release film. Next, the respective green sheets were stacked in order to correspond to the structure of the battery element shown in fig. 1 and 2, and then thermally pressed at 100 ℃ for 10 minutes. This makes it possible to obtain a laminate as a precursor of a battery element.

(sintering Process of laminate)

The obtained laminate was heated to remove the acrylic binder contained in each green sheet, and then further heated to sinter the oxide glass contained in each green sheet.

(Process for producing terminal)

First, Ag powder (chemical industry, university, japan) as conductive particle powder and oxide glass (Bi-B glass, asa glass, asaf 1096) were mixed at a predetermined mass ratio. Next, the obtained mixture was mixed with an acrylic binder at a mass ratio of the mixture (Ag powder + oxide glass) to the acrylic binder of 70: 30, and then mixed with a butyl acetate solvent so that the solid content became 50 mass%. Then, the resulting mixture was stirred with zirconia balls having a diameter of 5mm for 4 hours, thereby obtaining a conductive paste. Next, after the conductive paste was applied to a release film, the conductive paste was attached to the first and second end faces (or side faces) of the laminate in which the positive electrode current collecting portion and the negative electrode active material layer were exposed, respectively, and fired at 400 ℃ for 1 hour, thereby forming positive and negative electrode terminals. Thereby, the target battery can be obtained.

(evaluation 1: Capacity characteristics)

The capacity characteristic is a capacity characteristic shown when a battery cell is manufactured in a structure (main surface current collecting structure) in which the movement distance of electrons is only the amount of the electrode thickness. In other words, the capacity characteristic is a capacity characteristic when the secondary battery (particularly, the electrode) is assumed to have a primary surface current collecting structure. If the main surface current collecting structure is used, the extractable capacity of the one containing no conductive auxiliary agent is increased. This is because the contact area of the active material with the solid electrolyte is large. On the other hand, if a battery cell containing a conductive auxiliary agent in a positive electrode active material layer is fabricated in a primary surface current collecting structure in the same manner, the capacity decreases. This is considered to be because if the conductive aid exists at the active material-solid electrolyte interface, ion transport is hindered.

Specifically, the battery was charged with CCCV (constant current and constant voltage) at 4.35V to 0.01C at a current of 0.05C for the rated capacity, and after a 10-minute rest time was set, CC (constant current) discharge was performed at 0.05C to 3V, and the discharge capacity C at this time was evaluated. The relative capacity ratio R1 of the discharge capacity Cc1 in comparative example 1, which does not contain the conductive material in the positive electrode layer, was calculated assuming that the discharge capacity in each example/comparative example was Cx. The larger this ratio is, the more excellent the capacity characteristics are.

R1(％)＝{(Cx-Cc1)/Cc1}×100

R1 (%) was evaluated according to the following criteria:

very excellent: r1 (Excellent) 2% ≦ R1;

very good: r1 is more than or equal to-8% and less than-2% (preferably);

o: r1 is more than or equal to 11 percent and less than 8 percent (good);

and (delta): r1 is more than or equal to-20 percent and less than-11 percent (qualified (no problem in practical use));

x: r1 < -20 (practical problem).

(evaluation 2: load characteristics)

The load characteristics are load characteristics shown when the battery cell is produced using the main surface current collecting structure. In other words, the load characteristic is a load characteristic when the secondary battery (particularly, the electrode) is assumed to have a primary surface current collecting structure. If the main surface current collecting structure is used, the load characteristics are good when the conductive auxiliary agent is not contained. This is because the contact area of the active material with the solid electrolyte is large. On the other hand, if a battery cell containing a conductive auxiliary agent in a positive electrode active material layer is fabricated in a primary surface current collecting structure in the same manner, the load characteristics are degraded. This is considered to be because, if the conductive assistant exists at the interface of the active material and the solid electrolyte, ion transport is hindered.

Specifically, the capacity C at the time of charging at a current of 0.05C to the rated capacity and discharging at 0.05C was calculated _0.05 And capacity C at 0.2C discharge _0.2 The ratio of (b) Rx.

Rx(％)＝(C _0.2 /C _0.05 )×100

For the ratio Rx in each example/comparative example, the relative capacity ratio R2 to the ratio Rc1 in comparative example 1 in which the positive electrode layer does not contain a conductive material was calculated. The larger the ratio, the more excellent the load characteristics.

R2(％)＝{(Rx-Rc1)/Rc1}×100

R2 (%) was evaluated according to the following criteria:

very excellent: r2 (Excellent) 1% ≦ R2;

very good: r2 is more than or equal to-13% and less than-1% (preferably);

o: r2 is more than or equal to 18 percent and less than 13 percent (good);

and (delta): r2 is more than or equal to 40 percent and less than 18 percent (qualified (no problem in practical use));

x: r2 < -40 (practical problem).

(evaluation 3: theoretical Capacity ratio)

The theoretical capacity ratio is a ratio of discharge capacities extractable when a battery cell is produced in an end face current collecting structure with respect to a theoretical capacity calculated from the content of the positive electrode active material. The battery thus produced was charged with CCCV (constant current and constant voltage) at 4.35V to 0.01C at a current of 0.05C for the rated capacity, and after a 10-minute rest time was set, CC (constant current) discharge was performed at 0.05C to 3V, and the discharge capacity C at this time was evaluated. When Cx was calculated as the discharge capacity in each of examples and comparative examples, R3 was calculated as a relative capacity ratio with respect to the theoretical Capacity (CL) calculated from the content of the active material. The larger this ratio is, the more excellent the capacity characteristics are.

R3(％)＝(Cx/CL)×100

The discharge capacity ratio was evaluated according to the following criteria:

very excellent: a 98% ≦ ratio (excellent);

very good: the ratio of 90% to 98% (very good);

o: the ratio of 80 percent to 90 percent (good);

and (delta): the ratio of 60 percent to 80 percent (qualified (no problem in practical use));

x: the ratio was < 60% (practically problematic).

(comprehensive evaluation)

Of the evaluation results of the above evaluations 1 to 3, the lowest evaluation result was taken as a comprehensive evaluation.

Very excellent: the lowest evaluation result was ∈ (excellent);

very good: the lowest evaluation result was ∈ (very good);

o: the lowest evaluation result was ≈ (good);

and (delta): the lowest evaluation result was Δ (acceptable (practically no problem));

x: the lowest evaluation result was x (practically problematic).

< examples 2 to 22 and comparative example 1 >

Solid-state batteries were produced and evaluated in the same manner as in example 1, except that the type and content of the conductive material were changed as shown in table 1.

[ Table 1]

1 to 3 in the table are as follows:

1: the relative capacity ratio to the discharge capacity Cc1 in comparative example 1 in which the positive electrode layer contained no conductive material was the capacity shown when the main surface current collecting structure was employed.

2: the relative capacity ratio is a relative capacity ratio when the capacity of 0.2C in comparative example 1 in which the positive electrode layer does not contain the conductive material is taken as 100, and is a characteristic shown when the main surface current collecting structure is adopted.

3: the discharge capacity extracted in the end surface current collecting structure is taken as a ratio of the theoretical capacity calculated from the positive electrode active material content.

Industrial applicability

The solid-state battery of the present invention can be applied to various fields where electric storage is assumed. Although only exemplified, the solid-state battery of the present invention can be applied to the following fields: an electric/information/communication field using a mobile device or the like (for example, an electric/electronic device field or a mobile device field including a small electronic device such as a mobile phone, a smart phone, a notebook computer, a digital camera, an activity meter, an arm computer, electronic paper, an RFID tag, card-type electronic money, a smart watch, or the like); home/small industrial use (e.g., the field of electric tools, golf carts, home/nursing/industrial robots); large industrial applications (e.g. in the field of forklifts, elevators, port cranes); the field of transportation systems (e.g., the field of hybrid vehicles, electric vehicles, buses, electric trains, electric power-assisted bicycles, electric motorcycles, etc.); electric power system applications (e.g., fields of various power generation, load regulators, smart grids, general household installation type power storage systems, and the like); medical use (in the field of medical devices such as hearing aids for earphones); medical use (in the fields of administration management systems and the like); and an IoT realm; space/deep sea applications (e.g., space probes, diving research vessels, etc.), and the like.

Description of the symbols

10: electrode layer, 10A: positive electrode layer, 10B: negative electrode layer, 11: positive electrode collector, 20: solid electrolyte layer, 30: electrode separating portion, 30A: positive electrode separator, 30B: negative electrode separator, 40: terminal, 40A: positive electrode terminal, 40B: negative electrode terminal, 60: outer layer material, 100: solid battery laminate, 200: a solid-state battery.

Claims (10)

1. A solid-state battery comprising a solid-state battery laminate, a positive electrode terminal and a negative electrode terminal,

the solid battery laminate is provided with at least one battery constituting unit along the lamination direction, the battery constituting unit is provided with a positive electrode layer, a negative electrode layer and a solid electrolyte layer between the positive electrode layer and the negative electrode layer,

the positive electrode terminal and the negative electrode terminal are respectively provided on opposite side surfaces of the solid-state battery stack,

the positive electrode layer has an end surface current collecting structure for collecting current at an end surface of the positive electrode layer, and is in contact with a positive electrode current collecting portion at the end surface of the positive electrode layer and electrically connected to the positive electrode terminal via the positive electrode current collecting portion,

the positive electrode layer contains a conductive carbon material.

2. The solid-state battery according to claim 1,

the positive electrode layer and the positive electrode current collecting portion have the following structures: the end faces are in contact with each other, and are adjacent to each other in a direction perpendicular to the stacking direction in a cross-sectional view.

3. The solid-state battery according to claim 1 or 2,

the positive electrode current collector has an upper surface coplanar with the positive electrode layer in the stacking direction, and has a lower surface coplanar with the positive electrode layer.

4. The solid-state battery according to any one of claims 1 to 3,

the negative electrode layer is electrically connected directly to the negative electrode terminal at an end face of the negative electrode layer.

5. The solid-state battery according to any one of claims 1 to 4,

the conductive carbon material is at least one carbon material selected from the group consisting of a columnar carbon material, a granular carbon material, a hollow carbon material, and a sheet carbon material.

6. The solid-state battery according to any one of claims 1 to 5,

the content of the conductive carbon material is 0.5 mass% or more and 25 mass% or less with respect to the total amount of the positive electrode layer.

7. The solid-state battery according to any one of claims 1 to 6,

the conductive carbon material contains at least one carbon material selected from the group consisting of columnar carbon materials and granular carbon materials,

the content of the conductive carbon material satisfies at least one of the following conditions a1 or a 2:

condition a 1: a content of the columnar carbon material is 0.5 mass% or more and 12 mass% or less with respect to a total amount of the positive electrode layer;

condition a 2: the content of the particulate carbon material is 1.5 mass% or more and 8 mass% or less with respect to the total amount of the positive electrode layer.

8. The solid-state battery according to any one of claims 1 to 6,

the conductive carbon material contains at least one carbon material selected from the group consisting of columnar carbon materials and granular carbon materials,

the content of the conductive carbon material satisfies at least one of the following conditions B1 or B2:

condition B1: a content of the columnar carbon material is 0.5 mass% or more and 12 mass% or less with respect to a total amount of the positive electrode layer;

condition B2: the content of the particulate carbon material is 2.5 mass% or more and 5.5 mass% or less with respect to the total amount of the positive electrode layer.

9. The solid-state battery according to any one of claims 1 to 6,

the conductive carbon material contains one or more carbon materials selected from columnar carbon materials,

the content of the conductive carbon material satisfies the following condition C1:

condition C1: the content of the columnar carbon material is 0.5 mass% or more and 4 mass% or less with respect to the total amount of the positive electrode layer.

10. The solid-state battery according to any one of claims 1 to 9,

the positive electrode layer and the negative electrode layer are layers capable of inserting and extracting lithium ions.

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